Okay a question for the experts. I have a zone that hardly ever gets turned on( we like the bedroom cold). I am doing my twice yearly maintenance and check of the system. I turn the zone on but no water moves through it. Water does move through it with flushing through the radiant manifold. The pump cartridge gets warm when turned on but does not move water. This system is 8 years old and this pump has not been run more than 50 hours.\ Should I try replacing the cartridge or just go for the whole pumpthe whole pump.

try taking the cartridge out and manually turning the impeller, then turning it on to see if it turns. might be stuck.

Took out the cartridge and it will run free for a moment and then stick. I guess I will be replacing the cartridge. Thanks! Jill